The U.S. Department of Energy (USDOE) Office of Environmental Management (EM), Office of Soil and Groundwater (EM-12), is supporting development of the Advanced Simulation Capability for Environmental Management (ASCEM). ASCEM is a state-of-the-art scientific tool and approach that is currently aimed at understanding and predicting contaminant fate and transport in natural and engineered systems. ASCEM is a modular and open source high-performance computing tool. It will be used to facilitate integrated approaches to modeling and site characterization, and provide robust and standardized assessments of performance and risk for EM cleanup and closure activities. The ASCEM project continues to make significant progress in development of capabilities, with current emphasis on integration of capabilities in FY12. Capability development is occurring for both the Platform and Integrated Toolsets and High-Performance Computing (HPC) multiprocess simulator. The Platform capabilities provide the user interface and tools for end-to-end model development, starting with definition of the conceptual model, management of data for model input, model calibration and uncertainty analysis, and processing of model output, including visualization. The HPC capabilities target increased functionality of process model representations, toolsets for interaction with Platform, and verification and model confidence testing. The integration of the Platform and HPC capabilities were tested and evaluated for EM applications in a set of demonstrations as part of Site Applications Thrust Area activities in 2012. The current maturity of the ASCEM computational and analysis capabilities has afforded the opportunity for collaborative efforts to develop decision analysis tools to support and optimize radioactive waste disposal. Recent advances in computerized decision analysis frameworks provide the perfect opportunity to bring this capability into ASCEM. This will allow radioactive waste disposal to be evaluated based on decision needs, such as disposal, closure, and maintenance. Decision models will be used in ASCEM to identify information/data needs, and model refinements that might be necessary to effectively reduce uncertainty in waste disposal decisions. Decision analysis models start with tools for framing the problem, and continue with modeling both the science side of the problem (for example, inventories, source terms, fate and transport, receptors, risk, etc.), and the cost side of the problem, which could include costs of implementation of any action that is chosen (e.g., for disposal or closure), and the values associated with those actions. The cost side of the decision problem covers economic, environmental and societal costs, which correspond to the three pillars of sustainability (economic, social, and environmental). These tools will facilitate stakeholder driven decision analysis to support optimal sustainable solutions in ASCEM.

This study explores the development of a mechanical based system to retrieve single-shell tank waste at the Hanford site, located in Richland, Washington, without the addition of water. Out of 177 tanks at Hanford, there are 149 single-shell tanks (SST) and 28 double-shell tanks (DST). There are currently 67 SSTs that have leaked radioactive waste to the surrounding groundwater in the past or assumed to have questionable tank integrity. Leaking tanks continue to be a major concern as it was recently announced in February 2013 that six SSTs are leaking, even though they were believed to have been stabilized back in 2005. There are also several tanks with significant in-tank obstructions, such as air-lift circulators, where an arm-based retrieval would not be possible. All current methods of waste retrieval deployed involve the addition of significant amounts of water to generate a slurry that can be pumped out of the tank. This water, however, can exacerbate the leak and risk the potential of leaking more waste into the surrounding soil, subsequently contaminating the groundwater. It also reduces available waste storage space in DSTs, and increases the risk of dangerous buoyant displacement gas release events (BDGRE) in the headspace of DSTs. Focusing on leaking tanks, tanks with significant in-tank obstructions, and utilizing existing risers in Hanford’s tanks, this study evaluates commercially available dry technologies, such as augers and high-powered vacuums, for feasibility, safety, and efficiency of waste retrieval at Hanford.

The Philippine Nuclear Research Institute (PNRI) in collaboration with the interagency technical committee on radioactive waste has been undertaking a national project to find a final solution to the country’s low to intermediate level radioactive waste. The strategy adopted was to co-locate 2 disposal concepts that will address the types of radioactive waste generated from the use of radioactive materials. This strategy is expected to compensate for the small volumes of waste generated in the Philippines as compared to countries with big nuclear energy programs. It will also take advantage of the benefits of a shared infrastructure and R&D work that accompany such project. The preferred site selected from previous site selection and investigations is underlain by highly fractured “andesitic volcaniclastics” mantled by residual clayey soil which act as the aquifer or water bearing layer. Results of investigation show that the groundwater in the area is relatively dilute and acidic. Springs at the lower elevations of the footprint also indicate acidic waters. The relatively acidic water is attributed to the formation of sulfuric acid by the oxidation of the pyrite in the andesite. A preliminary post closure safety assessment was carried out using the GMS MODFLOW and HYDRUS softwares purchased through the International Atomic Energy Agency (IAEA) technical assistance. Results from MODFLOW modeling show that the radionuclide transport follows the natural gradient from the top of the hill down to the natural discharge zones. The vault dispersion model shows a circular direction from the vaults towards the faults and eventually to the creeks. The contaminant transport from borehole shows at least one confined plume from the borehole towards the creek designated as Repo1 and eventually follows downstream. The influx of surface water and rainfall to the disposal vault was modeled using the HYDRUS software. The pressure head and water content at the base of the foundation layer and the bottom of the concrete is where a significant reduction in water content can be observed. It is also noted that water content and pressure remain constant after one year.

The accident at the Fukushima Daiichi Nuclear Power Plant has raised questions about the accumulation of radionuclides in soils, the transfer in the foodchain and the possibility of continued restricted future land use. This paper summarizes what is generally understood about the application of agricultural countermeasures as a land management option to reduce the radionuclides transfer in the food chain and to facilitate the return of potentially affected soils to agricultural practices in areas impacted by a nuclear accident.

Soil is an essential component of all terrestrial ecosystems and is under increasing threat from human activity. Techniques available for removing radioactive contamination from soil and aquatic substrates are limited and often costly to implement; particularly over large areas. Frequently, bulk soil removal, with its attendant consequences, is a significant component of the majority of contamination incidents. Alternative techniques capable of removing contamination or exposure pathways without damaging or removing the soil are therefore of significant interest. An increasing number of old nuclear facilities are entering ‘care and maintenance’, with significant ground contamination issues. Phytoremediation — the use of plants’ natural metabolic processes to remediate contaminated sites is one possible solution. Its key mechanisms include phytoextraction and phytostabilisation. These are analogues of existing remedial techniques. Further, phytoremediation can improve soil quality and stability and restore functionality. Information on the application of phytoremediation in the nuclear industry is widely distributed over an extended period of time and sources. It is therefore difficult to quickly and effectively identify which plants would be most suitable for phytoremediation on a site by site basis. In response, a phytoremediation tool has been developed to address this issue. Existing research and case studies were reviewed to understand the mechanisms of phytoremediation, its effectiveness and the benefits and limitations of implementation. The potential for cost recovery from a phytoremediation system is also briefly considered. An overview of this information is provided here. From this data, a set of matrices was developed to guide potential users through the plant selection process. The matrices take the user through a preliminary screening process to determine whether the contamination present at their site is amenable to phytoremediation, and to give a rough indication as to what plants might be suitable. The second two allow the user to target specific plant species that would be most likely to successfully establish based on prevailing site conditions. The outcome of this study is a phytoremediation tool that can facilitate the development of phytoremediation projects, avoiding the need for in-depth research to identify optimal plant species on a case-by-case basis.

In 2009, remediation was initiated for a non-operational fuel cycle facility previously used for government contract work located in Windsor, Connecticut, USA. Radiological contaminants consisted primarily of high enriched uranium (HEU). Other radionuclides encountered in relatively minor amounts in certain areas of the clean-up included Co-60, Cs-137, Ra-226, Th-232 and low enriched uranium (LEU). Between 2009 and the spring of 2011, remediation efforts were focused on demolition of contaminated buildings and removal of contaminated soil. In the late spring of 2011, the last phase of remediation commenced involving the removal of contaminated sediments from portions of a 1,200 meter long gaining stream. Planning and preparation for remediation of the stream began in 2009 with submittal of permit applications to undertake construction activities in a wetland area. The permitting process was lengthy and involved securing permits from multiple agencies. However, early and frequent communication with stakeholders played an integral role in efficiently obtaining the permit approvals. Frequent communication with stakeholders throughout the planning and remediation process also proved to be a key factor in timely completion of the project. The remediation of the stream involved the use of temporary bladder berms to divert surface water flow, water diversion piping, a sediment vacuum removal system, excavation of sediments using small front-end loaders, sediment dewatering, and waste packaging, transportation and disposal. Many safeguards were employed to protect several species of concern in the work area, water management during project activities, challenges encountered during the project, methods of Final Status Survey, and stream restoration.

Tottori University and the Japan Atomic Energy Agency carried out jointly the feasibility study on phytoremediation techniques, which apply to soil contaminated by the TEPCO’s Fukushima Dai-ichi NPP accident. This paper illustrates the results from experimental investigations. Experimental investigations include both water-culture tests and field tests. Several plants, mainly halophytes that can specifically absorb more Na than K, and others like sunflower demonstrated for other domestic large-scale tests, were water-cultured and examined for screening. Easily cultivated and harvested plants without harmful effects on subsequent cultivation were also considered. New Zealand spinach was selected as a candidate for demonstrations in fields. The field tests were carried out at two sites of different agricultural types in Minami-soma, Fukushima prefecture. Concentration of 137 Cs in soil is about 4.5 Bq/g-dry as the average of 10 cm depth. The aims of the field tests are to confirm absorption ability and environmental adaptation of the test plants and to document the cost and performance of projects. In conclusion, the absorption of 137 Cs activity per unit area (Bq/m 2 ) by New Zealand spinach could be approximately 0.5%. To achieve an effective result in removal of 137 Cs from soil in around a decade, it is required to find the plant which has ten or more times higher absorption capacity than New Zealand spinach. From the consistency of both results in water-culture and field tests, the water-culture test can be valid for screening. In addition, applicable sites will be limited to fields which are too steep or too narrow to use mechanical diggers, and which are free from any restrictions to enter.

After the Fukushima Daiichi nuclear accident, Japan Atomic Energy Agency (JAEA) was chosen by the national government to conduct decontamination pilot projects at selected sites in Fukushima prefecture. Despite tight boundary conditions in terms of timescale and resources, the projects served their primary purpose to develop a knowledge base to support more effective planning and implementation of stepwise regional remediation of the evacuated zone. A range of established, modified and newly developed techniques were tested under realistic field conditions and their performance characteristics were determined. The results of the project can be summarized in terms of site characterization, cleanup and waste management. A range of options were investigated to reduce the volumes of waste produced and to ensure that decontamination water could be cleaned to the extent that it could be discharged to normal drainage. Resultant solid wastes were packaged in standard flexible containers, labelled and stored at the remediation site (temporary storage until central interim storage becomes available). The designs of such temporary storage facilities were tailored to available sites, but all designs included measures to ensure mechanical stability ( e.g. , filling void spaces between containers with sand, graded cover with soil) and prevent releases to groundwater (impermeable base and cap, gravity flow drainage including radiation monitors and catch tanks). Storage site monitoring was also needed to check that storage structures would not be perturbed by external events that could include typhoons, heavy snowfalls, freeze/thaw cycles and earthquakes.

In a green house pot experiment, the effects of three amendments, sulphur (S), ammonium sulphate ((NH 4 ) 2 SO 4 ) and ethylenediaminetetracetic acid (EDTA) were tested for phytoextraction of Cd and Zn by rapeseed ( Brassica napus L.). Elemental sulphur was applied as 20.00, 60.00, and 120.00 mg.kg −1 soil. EDTA was tested at a dose of 585.00 mg.kg −1 soil, and (NH 4 ) 2 SO 4 ) at a rate of 0.23 mg.kg −1 soil. All treatments received a base fertilization (Hogland) before sowing. Plants were harvested after 51 days of growth and shoot dry matter and soil samples were analysed for metal contents. All amendments caused a significant increase in Cd and Zn contents in plant shoots of all treatments than control treatment. Further, EDTA was most effective for extraction metals concentrations in shoot biomass but the plants showed significant signs of toxicity and yield were severely depressed. The addition of sulfur favorably influenced plant biomass production. The fertilized ammonium sulfate treatment resulted in the highest phytoextraction of Cd and Zn and the amounts of these metals accumulated in plant shoot exceeded by a factor of 4 and 3 respectively. Finally, Brassica napus could be used for soil remediation keeping its other uses which will make the contaminated site income generating source for the farmers.

This paper presents aspects of site decommissioning and clearance of a former fuel fabrication facility (development and production of fuel assemblies for research reactors and HTR) at Hanau (Germany). The main pathways for environmental contamination were deposition on soil surface and topsoil and pollution of deep soil and the aquifer by waste water channel leakage. Soil excavation could be done by classical excavator techniques. An effective removal of material from the saturated zone was possible by using advanced drilling techniques. A large amount of demolished building structure and excavated soil had to be classified. Therefore the use of conveyor detector was necessary. Nearly 100000 Mg of material (excavated soil and demolished building material) were disposed of at an underground mine. A remaining volume of 700 m 3 was classified as radioactive waste. Site clearance started in 2006. Groundwater remediation and monitoring is still ongoing, but has already provided excellent results by reducing the remaining Uranium considerably.

Because of the very low level of 90Sr in the environmental soil samples and its determination by beta counting may take several weeks, we developed a procedure for ultratrace determination of 90Sr using collision reaction cell-inductively coupled plasma tandem mass spectrometry (CRC-ICP-MS/MS, Agilent 8800). Soil samples were dried at 105 °C and then heated in a furnace at 550 °C to remove any organics present. 500 g of each soil samples were aliquoted into 2000 ml glass beakers. Each Soils samples were soaked in 2 ppm Sr solution carrier to allow determination of chemical yield. The solid to liquid ratio was 1:1. Finally the soil samples were dried at 105 °C. Five hundred milliliters concentrated nitric acid and 250 ml hydrochloric acid volumes were added on 500 g soil samples. The samples were digested on hot plate at 80 °C to prevent spraying with continuous manual mixing. The leachate solution was separated. The solids were rinsed with 500 ml deionized water, warmed on a hot plate and the leachate plus previous leachate were filtered and the total volume was reduced to 500 ml by evaporation. Final leachate volume was transferred to a centrifuge tubes. The centrifuge tubes were centrifuged at 3,500 rpm for 10 min. The leachate was transferred to a 1 L beaker and heated on a hot plate to evaporate the leachate to dryness. The reside was re-dissolved in 100 ml of 2% HNO3 and reduced by evaporation to 10 mL. The solution was measured directly by CRC-ICP-MS/MS by setting the first quadruple analyzer to m/z 90 and introducing oxygen gas into the reaction cell for elimination isobar interference from zirconium-90. The method was validated by measurements of standard reference materials and applied on environmental soil samples. The overall time requirement for the measurement of strontium-90 by CRC-ICP-MS/MS is 2 days, significantly shorter than any radioanalytical protocol currently available.

Contaminated soils form a large part of the nuclear waste arising from decommissioning activities. The storage and disposal of these large volumes of waste is costly. For this reason techniques which can decontaminate this waste stream to free release levels are economically very interesting. A feasibility study of the possibilities of soil washing to decontaminate such soils was ordered by NIRAS/ONDRAF and performed at Belgoprocess in collaboration with DEC. Initial contamination level and particle size distributions of contaminated soils from three different sources were determined. The main isotopes detected with gamma spectrometry contained in the waste were 241 Am, 137 Cs, 226 Ra, 60 Co and 232 Th. The particle size distribution revealed that more than half of the mass of the quartz sand that makes up the soil has a particle size between 125 and 212μm. This fraction is less contaminated than the fractions containing smaller particles. However, separation of the fines fraction (< 125 μm) was not enough to achieve the free release limit. Soil attrition was tested as an extra decontamination step for the sand fraction. The removal efficiencies for the different radionuclides contained in the soil were measured. The process conditions were optimized to achieve maximum removal and a treatment method for the secondary waste coming from this process step was determined. The soil washing process was not only performed with water but also with nitric acid to assess the possibilities of a combination of a mechanical and a chemical decontamination process. Reduction efficiencies of 60–80% for the most relevant radionuclides were recorded.

India is one of the developing countries operating site remediation techniques for the entire nuclear fuel cycle waste for the last three decades. In this paper we intend to provide an overview of remediation methods currently utilized at various hazardous waste sites in India, their advantages and disadvantages. Over the years the site remediation techniques have been well characterized and different processes for treatment, conditioning and disposal are being practiced. Remediation Methods categorized as biological, chemical or physical are summarized for contaminated soils and environmental waters. This paper covers the site remediation techniques implemented for treatment and conditioning of wastelands arising from the operation of nuclear power plant, research reactors and fuel reprocessing units.

SOGETER is a waste conditioning process for Low Level radwaste (LLW) or Intermediate Level radwaste (ILW) such as sludge, soil, ashes, evaporator concentrate, concrete rubble, asbestos or sand. Such radioactive waste is usually solidified into a cement matrix, resulting in a 2 to 5 times volumetric waste increase, i.e. 1 m 3 of initial raw waste generates 2 to 5 m 3 of solidified waste. Sogeter melts the waste at high temperature - up to 2000 K, and produces a synthetic rock. The main component of the matrix is the waste itself; therefore 1 m 3 of initial raw waste generates only 0.2 to 0.5 m 3 of solidified waste. Compared to cementation, synthetic rock decreases the volume to be disposed of by a factor of 4 up to a factor of 25. By mixing different types of waste, or using additives, the composition of the waste is adjusted so that a fluid melt is obtained at temperatures less than 2000 K and the final 200 L ingot can be cooled within 2 days, without shattering or disaggregating. A wide range of compositions have been tested demonstrating that almost every type of waste can be conditioned with Sogeter. An industrial facility has been designed based on very robust and proven heating and off-gas treatment technology. Industrial tests have been carried out on more than 2 tons of simulated, non-radioactive waste, producing blocks of treated matter weighing up to 250 kg. During these tests all process parameters, including electrical consumption, throughput and robustness, have been checked.

The National Radioactive Waste Storage and Disposal Site was established in 1959 in the Faizabad region approximately 50 km east of the capital, Dushanbe. The site is located on the southern flank of the Fan Mountains facing the Gissar Valley in a sparsely populated agricultural area, with the nearest villages located a few km from the site. The site was initially designed to accept a wide range of contaminated materials, including obsolete smoke detectors, sealed radioactive sources, waste from medical institutions, and radioactive liquids. Between 1962 and 1976, 363 tonnes and 1146 litres of material, contaminated with a range of radionuclides were shipped to the site. Between 1972–1980 and 1985–1991, ∼4.8 × 10 14 and 2 × 10 13 Bq, respectively, were shipped to the site. An additional 7 × 10 14 Bq was shipped to the site in 1996. Partly as a result of the dissolution of the former Soviet Union, the disposal site had fallen into disrepair and currently presents both an environmental hazard and a potential for the proliferation of radionuclides that could potentially be used for illicit purposes. Remediation of the disposal site was started in 2005. New security fences were erected and a new superstructure over an in-ground storage site constructed. A central alarm monitoring and observation station has been constructed and is now operational. The geology, flora, and fauna of the region have been documented. Radiation surveys of the buildings and the storage and disposal sites have been carried out. Samples of soil, surface water and vegetation have been taken and analyzed by gamma spectrometry. Results show a slight extent of contamination of soils near the filling ports of the underground liquid storage container where a Cs-137 concentration of 2.3 × 10 4 Bq/kg was obtained. Similar values were obtained for Ra-226. Radiation fields of the in-ground storage site were generally <1 μSv/h with 8% exceeding this value. Neutron radiation levels at the same location were also low with a few readings exceeding 10 μSv/h. The volume of liquid waste is estimated to be ∼140 m 3 . Most of the activity appears to be associated with the sediments in the tank. Suggestions are presented for the immobilization of the liquid wastes and long-term monitoring of the site and the surrounding territory.

The US Department of Energy Office of Environmental Management has supported independent technical reviews of soil and groundwater projects at multiple DOE sites over the last 10 years. These reviews have resulted in significant design improvements to remedial plans that have accelerated cleanup and site closure. Many have also resulted in improved understanding of complex subsurface conditions, promoting better approaches to design and implementation of new technologies. Independent technical reviews add value, because they provide another perspective to problem solving and act as a check for especially challenging problems. By bringing in a team of independent experts with a broad experience base, alternative solutions are recommended for consideration and evaluation. In addition, the independence of the panel is significant, because it is able to address politically sensitive issues. The expert panel members typically bring lessons learned from other sites to help solve the DOE problems. In addition, their recommendations at a particular site can often be applied at other sites, making the review even more valuable. The review process can vary, but some common lessons ensure a successful review: • Use a multi-disciplinary broadly experienced team; • Engage the panel early and throughout the project; • Involve regulators and stakeholders in the workshop, if appropriate; • Provide sufficient background information; • Close the workshop with a debriefing followed by a written report. Many groundwater remediation challenges remain at DOE sites. Independent technical reviews have and will ensure that the best capabilities and experience are applied to reduce risks and uncertainties.

Much of Azerbaijan’s Absheron Peninsula is contaminated by natural U-series and Th-series radionuclides, released in the production of oil and gas and, to a lesser extent, by anthropogenic radionuclides, including Sr-90 and Cs-137, from local industrial activities and trans-border transport. The region contains a large number of pipelines and artificial lagoons that have been used to retain excess groundwater and oil residues. In spite of the long history of the oil and gas industry, radioecological investigations have not been carried out until recently. The purpose of this project is to determine the extent of radionuclide contamination in the Absheron Peninsula using a combination of radiation field measurements and laboratory analyses of selected samples, focusing on ten routes in the vicinity of Baku. The routes were selected as most likely to have become contaminated over time. Soil samples, taken from surface and to a depth of 1 m, aqueous samples from surface waters and marshes, and aqueous and sediment lagoons that showed elevated dosimetry readings, were prepared for gamma spectrometric analysis. Control samples were taken from non-contaminated areas. Samples of air and surface waters were analyzed for Rn-220 and Rn-222. The data will then be used to assess the potential impact of the contamination on the local population. A total slightly 4000 dosimetric readings were taken during the course of this investigation. Of these, 1366 (34%) exceeded 5.4 μR/h. This level is two standard deviations above the mean of the least contaminated route, the 79-km Baku-Guba route. Along the routes Baku-Shemakha and Baku-Guba where no oil and gas activity had taken place, radiation levels of 5.1 ± 1.5 and 4.2 ± 0.6 μR/h, respectively, were obtained. The readings for the route Baku-Guba were then used as representing negligible contamination to which the readings of the other sites were compared. In contrast, along the routes Baku-Lokbatan and Baku-Surakhani, that have seen oil- and gas-related activity, radiation levels were sometimes two or three orders of magnitude higher. The most highly contaminated sites were those of two abandoned iodine recovery facilities along the route Baku-Surakhani, the Ramani and Surakhani sites where readings up to 1450 μR/h were obtained. The contamination is due mainly to uranium and thorium in the formation water associated with the oil and gas. Radon measurements did not exceed 20 Bq/m 3 .

Geostatistics meets a growing interest for the remediation forecast of potentially contaminated sites, by providing adapted methods to perform both chemical and radiological pollution mapping, to estimate contaminated volumes, potentially integrating auxiliary information, and to set up adaptive sampling strategies. As part of demonstration studies carried out for GeoSiPol (Geostatistics for Polluted Sites), geostatistics has been applied for the detailed diagnosis of a former oil depot in France. The ability within the geostatistical framework to generate pessimistic / probable / optimistic scenarios for the contaminated volumes allows a quantification of the risks associated to the remediation process: e.g. the financial risk to excavate clean soils, the sanitary risk to leave contaminated soils in place. After a first mapping, an iterative approach leads to collect additional samples in areas previously identified as highly uncertain. Estimated volumes are then updated and compared to the volumes actually excavated. This benchmarking therefore provides a practical feedback on the performance of the geostatistical methodology.

When out of normal material or very high activity is encountered in a Deactivation & Decommissioning (D&D) project, special considerations are needed. As the source term increases, the level of attention to planning, project cost and risk management must increase as well. WorleyParsons (WP) is engaged in identifying, screening and documenting (with follow on project design expected) the various remediation methods available to remove highly contaminated soils discovered under a hot cell. Soil dose rates have been measured in the 70 to 100 Sieverts/hour range, with radionuclide mix to be defined in mid to late summer 2011 from samples collected in June 2011. The scope of this project is to identify remedial techniques and removal methods (means and methods) and develop a set of technically implementable remedial alternatives (alternatives). These remedial alternatives will be screened by a Technical Panel consisting of WP and client experts using a WP defined screening process to narrow the list of alternatives. Transparency and un-biased choice of actions is key to owner and public confidence in the process and the choice of the ultimate path forward. The poster will show Phase 1 — how potential remedial techniques and removal methods (means and methods) were first identified, catalogued and initial screened. Following the initial screening, the remaining means and methods are combined to form an alternative — a stabilization means with a removal method are matched with a waste container to from an alternative. A rough order of magnitude (ROM) cost estimate and high level schedule are also developed for each alternative. In parallel with the above, screening criteria with associated design attributes were identified and given a weight factor and attribute value, which are then multiplied together and used to develop a decision matrix for the developed alternatives. Two parallel processes — screening criteria development and alternative development — are being pursued to allow better focus on each while not prejudicing the final alternative selection. Phase 2 actions — the expert panel - grade each alternative against the pre-approved screening criteria using the decision matrix that compiles results — real time but blind to the panel. The top two to four scores from this last effort will proceed to a pre-conceptual, conceptual design phase and the expert panel reconvened to make the final decision on the remediation methods to be used for removing the soil / contamination.

The Active Storage Facility for Residuals (Aktives Lager fu¨r Ru¨cksta¨nde – ALfR) — an open-air controlled area — was used for the storage of radioactive waste (liquid and solid waste) at the site of the NPP Rheinsberg in the former GDR. Liquid waste was cemented and dumped for near surface final disposal. During the period of operation of the ALfR some incidents happened. Residues of evaporated cooling water of unknown amount (ca. 1–10 m 3 ), the drop-out from small leakages and the wash-off from contaminated open-air storage barrels contaminated the soil. Since 1997 the buildings of the ALfR have been decommissioned and the site will be remediated. From the beginning of decommissioning up to now the groundwater has been monitored. This paper shows different steps of decommissioning and explains the results of groundwater monitoring. Currently 33 sampling points are being used for sampling groundwater from different layers. The radiological parameters under examination are Cobalt-60, Cesium-137, Strontium-90 and Tritium. Non-radiological parameters like Bore, Potassium, Sodium, Nitrate, pH value and TOC (total organic carbon) are also being investigated. Since 1997 the activity concentration of Cobalt-60 and Tritium in the groundwater has been decreasing. The activity concentration of Strontium-90 had increased from 1997 to 2007. Since 2007 activity concentration of Strontium-90 has been decreasing. 350 m away from the ALfR, in the direction of groundwater flow, the Lake Stechlin is located in a nature protection area. The groundwater beyond the ALfR-site is not used as drinking-water and up to now there has been no detectable contamination of Lake Stechlin. Therefore there is no radiological impact on humans by contaminated groundwater. The hypothetic effective dose of Cobalt-60, Tritium and Strontium-90 resulting from postulated consumption of groundwater was determined using consumption rates according to the German Radiation Protection Ordinance. In case of using the groundwater as drinking-water the annual effective dose is 0,4 mSv/a at a postulated drinking-water well on the ALfR-site and 2,5 μSv/a at a postulated drinking water well in a distance of 142 m. Results of the observations: The observations of direction and velocity of the flow of the ground-water principally confirms the transportation model made at the beginning of decommissioning of ALfR. In vertical direction, the real spread of contamination in the groundwater is smaller than assumed. The dilution of Co-60 is higher than assumed. In contrast to the assumptions of the transportation model, Cesium-137 has a lower mobility.